Rotary excavator



.Marh 30,'1943.' L; G. MORSE ETI-I\L ROTARY EXCAVATOR 3 Sheets-Sheet 1Filed April 2, 1940 IN VEN TORS:

A. d/Ifo/JJ A TTORNEX March 30, l943- L. G. MORSE ET AL 2,315,007

' ROTARY EXCAVATOR Filed April 2, 1940 3 Sheets-Sheet 2 7/ m '14INVENTORS:

- i CC M251;

ATTORNEY March 30, 1943. L. G. MORSE ET AL ROTARY EXCAVATOR Filed April2, 1940 3 Sheets-Sheet 3 INVENTORS:

v ATTORNEY Patented Mar. 30, 1943 ROTARY EXCAVATOR.

Leslie G. Morse, Randolph, Arthur It. Hill, Brookileld, and Charles C.Morse, Randolph, Vt.

Application April 2, 1940, Serial No. 327,534

- Claims.

The invention has for an object to present improvements in rotary snowplows, and in particular to evolve novel features of functionalimportance to improve the action of such devices.

It is a particular aim to enable the production oi such an articlereadily in a small size to be used for clearing sidewalks and adapted tobe embodied on a small pedestrian-guided power tractor, although it isalso adapted to be constructed in larger sizes and for connection orincorporation on four-wheel or other large tractors.

An important aim of the invention is 'to present such a device which isadapted to deposit snow immediately beside the cleared path whennecessary, as well as to throw it to a great distance, so that thedevice is well adapted to use in urban areas, whereas the ordinaryrotary plows are so constructed and so operative that they are not welladapted to such use, although they may be satisfactory in country areas,as far as the deposit of snow is concerned. This invention isconsequently highly desirable for sidewalk clearing without throwing thesnow promiscuously, which would involve covering or soiling of lateralwall ss, windows, or other areas and structures.

A special aim is to present a machine of this kind which is adapted tooperate effectively with low power operating the rotor, due to specialnovel features in construction and arrangement of parts.

It is also an important object to present a. novel coordination of asimple two-wheeled tractor and the attachable plow unit to the end ofassuring the proper fit of the plow element to the pavements beingcleared, throughout undulations, affording support to the tractor powerplant in a novel way. and permitting lifting of the plow manually with aminimum of eflort.

It is an important aim to present a novel coordination of a rotary snowthrower and a plow shoe, with respect to the path to be cleared and withrespect to the tractor device.

A further important object is to present a novel construction in thesnow-throwing rotor, and in the construction of the plow shoe or pusher.1

It is also an object to present an attachable rotary plow unit which maybe readily attached and detached from a tractor.

Additional objects, advantages and features of invention reside in theconstruction, arrangement and combination of parts involved in theembodiment of the invention, as will be understood from thefollowing'description and accompanying drawings, wherein Figure 1 is afront view of a plow unit constructed in accordance with the invention,in operative position as it would be when connected to a tractor.

Figure 2 is a right hand side elevation of a complete coupledtractor-plow unit as heretofore constructed; parts of the tractor powerplant and of the plow power plant being shown in outline only and partof one wheel being broken away.

Figure 3 is a similar view of the tractor-plow from the opposite sidewith the rear portion of the tractor broken away.

Figure 4 is a top view of the plow unit.

Figure 5 is an enlarged front elevation of the rotor.

Figure 6 is an edge elevation of the rotor.

Figure 7 is a detail of the pivotal connection of the plow unit andtractor, showing the spring connection between the tractor frame andplow unit.

Figure 8 is a diagrammatic view of the tractor and plow unit connectionsand having another relative position of the two dotted to show thenature of the relative movement of the two in accommodating the plow tocurved pavement surfaced or variously inclined surfaces.

Figure 9 is a detail of one of the runner shoes and its adjustablemounting on the plow unit.

The tractor There is illustrated a part of a standard tractor unitcommercially available, including of the running gear, however, only therear or tractor wheels 20. These wheels support in the usual way aninternal combustion power plant-transmission unit 2|, steering handles22, and control and gear shift levers 2324 on one handle. The center ofgravity of the power-transmission unit in this instance is preferablyrearwardly of the axis of the wheels 20, so that a partialcounterbalance is thereby provided for our attachable plow unit, andenabling our plow unit to be lifted from the ground by downward pressureof the operator on the handles 22. The tractor unit has fixed thereon ateach side a pivot plate 25 in which a heavy pivot stud or bolt 26 isengaged, serving as the main connection between the tractor unit and theplow unit, as will be described. The tractor unit also has mounted onits forward end a forwardly projected flange bracket 21 serving as partof a compensating resilient support for the front of the tractor unitand lift for the plow unit as will appear.

Plow frame and power unit The plow unit comprises a rigid body framework 30, which may be variously designed, but in the present instanceincludes two main lower side members 3| which extend rearwardly besidethe pivot plates 25, and carry bearings 32 in which the bolts or studs25 are engaged. At the forward part of the frame 30 there is included achannel girder 33 set transversely across the forwar extremities of theside members 3| in the present instance at right angles to thefore-andaft axis of the tractor. It is disposed with its body or web ina substantially vertical plane, and its top and bottom flanges 34,extending rearwardly. The bracket 21 extends close to the web of thechannel member for relativevertical movement, and includes a transverseflange portion against the underside of which there is engaged a coiledload supporting spring 36 seated on the lower flange 35 of the channelmember, while over the bracket flange there is a coil spring 31, whichmay be of lesser vertical extent and may be of less strength but ispreferably under some compression between the top flange 34 of thechannel member and the bracket 21 at all times. A vertical shaft 35 isfixed removably in the flanges 34, having a cotter pin through each endin the present instance. It is engaged loosely and axially through bothof the springs 35 and 31 and slidably through the bracket 21 which isproperly apertured for the purpose. The frame 30 includes a top bedportion consisting of two members arranged transversely of the machinein the present instance and longitudinally slotted to receivefastenings43 of the base 33 of a conventional power plant 40, preferably includingan internal combustion motor, intended to operate the rotor or snowthrower of the plow unit independently of the power plant of the tractorunit. The details of this power plant comprise no novel part of thisinvention, and are not shown, it being sumcient for it to have thenormal controls by which it may be set in operation to drive the rotorof the plow at a speed appropriate to the nature of the material to beexcavated. It includes a main shaft projected forwardly and having apulley 4| in a plane parallel to the web of the channel member 33 andrearwardly of the plane of the rear edges of the fianges34-35.

The channel member 33 projects a considerable distance to the right fromthe side members 33, and beyond the track or path of the right handwheel of the tractor unit, and spaced to the rear of this laterallyprojected end of the channel member there is mounted as a fixed part ofthe frame 30 a shorter section of similar channel stock 43, parallel tothe first and projecting across the path of the adjacent wheel. In thepresent in stance it is welded to an upright 42 of the frame whichsupports one side of the bed portion 38 of the plow'power plant. Toassure the rigid parallel relation of the two channel pieces they areconnected at top and bottom at their outer parts by tie bars 44. Inbearings 45 of appropriate design fixed on the webs of the two channelmembers, a rotor shaft 45 is journalled, on

which there is fixed a large pulley 4I alined with the pulley 4 I. Inthe present instance, these pulleys are shown as having a plurality ofgrooves, and they are connected by a corresponding number of v-belts 48.For adjusting the tension of these belts the base 39 may be slidablyadjustable on the bed 38and secured adjustably by the usual bolts 49 bywhich the base is clamped to the bed 38.

It should be noted that the plow unit power plant is disposed centrallywith respect to the longitudinal axis of the tractor unit, and that thebed portion 38 is extended rearwardly from the supporting frame 30 sothat the center of gravity of the plow power plant is located over thetrantor power plant and the weight forwardly of the wheels 20 isminimized as much as practicable.

Rotor housing and chute Fixed to the shaft 48 there is a rotor 50,around which a casing 5| is built, including a concentric lowerperipheral wall 52 which extends with auniform width for approximately190 degrees around I, the path of the rotor, although this may be variedwithout materially affecting the operation of the machine. Thisperipheral wall is joined fixedly to a rear or back planiform wall 53,which is secured to the channel member 33. A' vertical continuation ofthe wall 52 stops short and forms a. right hand horizontal top edge 54at or near the level of the top of the rotor, and at its inner or leftside it is continued upwardly toward the right from a level just above,forming a chute wall 55 in a plane atan angle of between 25 and 30degrecs to the vertical in the present instance (although this may bevaried).. It stops at a line slightly to the right of a vertical linethrough the axis of the rotor. In the present instance, this planiformpart 55 is tangent to the arc of the peripheral wall 52, and the backwall 53 is continued upwardly a similar distance and joined thereto. Aparallel corresponding upper front wall 55 is joined to the forward edgeof the chute wall 55, the lower edge of this front wall being trimmedhorizontally at the same level as the edge 54 in this instance. Thiswall 55 and the wall 52 therefore form an opening at the front side ofthe casing, exposing the rotor at its front side. The upper right handedge of the wall 52 stops at about the level of a horizontal radius ofthe rotor, and the continuation thereof upwardly is formed by a verticalthicker side shoe plate 52, (to be described) which thus extends at atangent upwardly completing the casing 5| to the edge 54 which is thusthe top edge of the shoe plate. The right han edges of th walls 53 and53 are inclined slightly toward the left at an angle of between five andten degrees, although this may be omitted or varied, as desired. Sincethe wall 52 stops near a level with the upper side of the rotor, anopening 58 is thus formed extending to the top of the plate 55, throughwhich snow and air may be discharged by the rotor as will be described.Pivoted on the walls 52 and 56 near their right hand edges, there is adirecting or deflecting hood 50 consisting of two sector shaped itudinalaxis of the tractor unit, and in fact,

the outer termination of the peripheral wall of the rotor case, at 4, islocated well outwardly of the plane or' track of the right hand wheel20. In consequence, the belts 48 extend diagonally downward from theplow power plant, as may be seen in Figure 1. The left side of thecasing 5| is adjacent the medial line of the path of the tractor. Theback plate 53 has its right hand edge at the lower part joined to andstopping at the right hand shoe plate 82 of the plow proper, this shoeplate extending downwardly a distance below the lowest part of the wall52, and having a runner shoe 15 mounted thereon for vertical adjustmentas will be described. The shoe plate may extend forwardly at its lowerpart a distance, its forward edge being inclined backward to the loweredge of the wall 56, which is secured thereto. The forward edge of theside plate 82 may be reinforced by a sharpened removable blade edge 63as shown, and at its lowermost forward part the plate 62 has fixedthereon a replaceable shoe blade 64 extending forwardly from the plate82 and formed with a runner edge curved upwardly and forwardly, asshown.

Around the lower front edge portion of the wall 52 next to the side shoeplate 62, a suitable snow guide plate 65 is provided, united with thewall 52 and the plate 62, stopping short at its edge above the lowerlevel of the blade 53. On this plate there are replaceably fixed twoblades 66 and 51, respectively, one extending downwardly and' forwardlyfrom the lower central part of the wall 52, while the other similarlyinclined, extends laterally from one 65 to immediately adjacent theforward termination of the side plate 62, the blade 53 extending adistance forwardly thereof. The parts 82 to 51 inclusive constitute acontinuation or right end portion of the plow, now to be described.

The plow At the left hand side of the casing wall 52, a laterallyextended plow or plow arm is mounted, of the same height as the sideshoe plate 62 and comprising a plate 51 curved so that its lower partslopes forwardly and downwardly, while its upper part slopes forwardlyand upwardly, its lower edge, however, advanced more than its upperedge. It is extended from the casing 5| laterally and forwardly towardthe left at a horizontal angle of about 50 degrees to the fore-and-aftaxis of the apparatus, which axis is coincident with the path of thetractor. The curvature of the plate 10' corresponds with that formed bythe geometrical projection of the forward edge of the wall 52 in thedirection in which this plow arm 10 is extended horizontally. At itslower edge the plow is provided with a plate 62 is spaced beyond theplane and track of the right wheel 20. In a machine constructed in theproportions shown to clear a swath three feet in width, the left sideofthe plow or shoe plate 89 is about three and one-half inches outwardlyof the left wheel track, and the right hand side shoe plate 52 is aboutnine inches outwardly of the right hand wheel track. This side shoeplate likewise has a forwardly pro jected shoe blade H' at its lower ede formed like the shoe blade 54 before referred to, and is extendedbackwardly of the shoe blade H sufficiently to afford a mounting for avertically replaceable blade 68, and its upper edge may a lesserdistance outwardly of the plane or track of the left wheel 20 than theright hand shoe adjustable runner shoe '2 similar to the one 15 beforereferred to at the right hand side.

The plow arm 10 is suitably supported in fixed angular relation to theframe 30, which includes in the present instance, struts 13 extendingfrom the forward part of the frame 30 to a plate 14 fitted and welded tothe rear face of the plate 88, and the side shoe plate 69 is braced by astrut I5. Each of the runner shoes 12 and 15 consists of a short runnerproper 16, having front and rear ends curved upwardly and a centralintegral vertical standard 'I'I united therewith, and which may comprisea portion of channel iron, U-shaped in horizontal section with the sideflanges presented outwardly toward or against the inner face of therespective side shoe plates. Reinforcing webs H are provided between theends of the runners and the standards. On the plates 62 and 69there arefixed guide blocks 18 slidably in the channels .of the standards, and abolt 19 is engaged through each shoe plate and block 18 and through avertical slot in the standard, a nut being engaged on the bolt to clampthe standard in adjusted positions.

The rotor The rotor 50 in the present instance comprises a planiformcircular plate--a diso8l, having a hub 82 fitted to the forward end ofthe shaft 46, and fixed against rotation thereon in any approved way.The disc 8| has removable blades 83 mounted thereon (four in thisinstance) and the diameter of the disc is equal to the radius of theblades for a special function which will appear. Each of the bladesconsists of a sheet metal blank substantially rectangular in shape, themajor body portion being planiform, and one edge portion being bent atright angles to provide a foot flange 8,4 apertured to receive bolts bywhich it is attached removably to the disc 8|, while its opposite edgeportion is curved laterally toward the opposite side from the footflange, forming an advance draft and slicing edge 85. Welded to the backside of the blade near the slicing edge there are two struts 86, whichextend to the outer edge of the respective foot flange-of the blade andare welded thereto. The struts are also in the present instance inclinedfrom the ends of the blade slightly so as to clear the space over thefoot flange 84 at the ends, while supporting the extreme end corners ofthe blade, especially the radially'outer corner at the slicing edge. Thestruts may be otherwise placed or the blade otherwise braced inaccordance with 85 as shown has the effect of drawing the snow inwardtoward the disc when the device is in operation, at the same time thatthe fiat parts of the blades propel and develop centrifugal force in themass of snow to throw it outwardly, and the rotor also acts as a fan todraw air inward with the snow-and blow it outward, so that the airserves as a carrying medium for the snow. Welded to the back of eachblade there are two fingers 88, projecting horizontally forwardtherefrom which have been formed of inch steel rod stock. The one nearthe outer end of the blade has been extended about two and one-halfinches forwardly beyond the edge 85 of the blade l3, and the one nearthe hub of the rotor has been so extended about one inch and a half,although these proportions may be varied as discretion dictates.

The hood, chute, and plow body parts, including the side shoe may bemade of sheet aluminum for extreme lightness, and to avoid corrosion, ora rustless steel may be used without the device becoming too heavy forhandling by a single person with great ease. The blades of the rotor arepreferably of steel suited to the use.

p ration The machine being assembled as described and a tractor such asindicated being available, the plow is coupled by moving the tractorinto place behind the plow, removing the shaft 25, and pivot couplingbolts 2i, then adjusting the bracket 21 between the springs 25-31. andreinserting the shaft 35, then securing it by cotter plus. The bolts 26are then put in place in the bearing 32 and securing them to the plates25.

The motor of the tractor unit is then started preparatory to moving themachine to the scene of operation, and the motor of the plow lmit may bestarted at the same time, or it may be started after reaching the placewhere operation of the rotor is required. It is contemplated to adjustthe throttle of the motor of the plow unit so as to operate at apredetermined speed when in advance of the plow proper, packing acertain amount of it downward and aiding in the support of the plow, butmore especially intended to sever packed snow near the ground, so thatthe portion in the path of the advancing plow may be more readily movedto the rotor. It will be seen that in the present embodiment the righthand one-half of the snow in the path to be cleared may move directlyinto the rotor, while the left half is engaged by the plow I0 and movedby the plow to the right, so that the snow in the right half of the pathis crowded toward the right hand side shoe plate by the snow movingconvergently thereto along the face of the plow arm 10. This condensesthe snow somewhat and enables the rotor to work more effectively on themass of snow to be moved. In case it is desired that the level of snowin the path cleared be higher-that is, if a deeper layer of snow isdesired to be left in the path cleared-the runners 12 and 15 areadjusted downwardly further on their mountings.

As the machine moves forwardly, the rotor turning in a counter-clockwisedirection as viewed in front-of the machine, the snow is concentrated inthe opening, and the advancing machine brings the slicing edges of theblades of the rotor into engagement with the snow, each one shaving oil!a certain'amount from the face left by the preceding blade. The fingers88 are valuable in loosening heavy (wet) snow, which tends to becomeblocked in advance of the blades 23. The sliced-ofl snow is thrownrearwardly toward the rotor disc 50, and also being moved through snowof uniform depth as involved in a particular area to be cleared, andthis might be diflerent for diiferent depths of snow 01' qualitythereof. If however, the plow motor is equipped with an automaticgovernor, the latter may be set to maintain a predeter mined properspeed under load which may be the same for various depths. It may,however, be deem d desirable to set the governor for a higher, speedthan normal where exceptionally deep and heavy or packed snow ispresent. .But the load on the plow rotor may be governed by the speed ofprogression of the tractor unit.

The two motors being in operation, the tractor clutch and gearing areengaged so as to move the assembly forward at the desired speed with theopening 52 presented in the direction in which snow is to be thrown,while the operator manipulates the handles 22 to lower the blades 65-52to the proper level, where they will be supported by the runner-shoes l2and I5 and also the runner portions of the blades .N-ll.

' It will be noted that the runners 12-15 are located inwardly on theswath cleared by the machine while the rlmner portions of the blades64-" engaging snow outside the swath are sufflciently narrow notto liftthe plow above the position determined by the adjustment of the runnersl2 and 15. The latter will usually run on a thin layer of snow leftbelow the blades 5! and 52, and the runner portions of the blades 'IIand El will project into fresh undisturbed snow carried forwardlycounter-clockwise by the advancing blade by which it was sliced. Thecentrifugal force set up in the snow thereby causes it also to packagainst the wall 52 upon which it slides until it reaches the tangentportion 55, whereupon it moves outwardly beyond the radius of the bladeby which it was impelled, and slides with great velocity against thechute plate 55 until it clears the upper end thereof. At the same time-abody of air entrained and impelled by the blades sweeps the snow alongand from the opening 55 at the extreme upper part. When the hood 6| isfully retracted, as in Figure 1, the path of the snow upwardly beyondthe machine approximately coincides with the slope of the chute plate 55for a few feet, and then curving toward the right to a maximum height,the snow dropping and settling upon surfaces at varying distances fromthe machine. When the hood 6!! is adjusted further toward the right, thesnow sliding upwardly along the chute plate 55 is deflected in a lesssteeply inclined path and falls at a shorter distance fromthe machine.

The fingers ll serve to slice up or break up heavy snow and slush sothat such material will not become so packed in front; of the rotor thatit cannot move into engagement with the blades as the machine is movedforward. In light, dry snow the fingers are not essential, but do notinterfere with the proper movement of such snow into the rotor, or itseffective engagement and discharge from the machine as described.

In order that the snow may be most effectively and finely broken upbefore the rotor, the fingers 88 may be staggered on successive blades,and either additionally or alternatively they may be variously bent inthe direction of intersecting radii of the rotor, so as to move indifferent paths from the paths of following fingers as the rotor turnson its shaft. As shown, the inner finger on one blade is bent outwardlyaway from the larly, or in any other degree or direction.

On the next blade the inner finger is bent inv wardly toward the rotorcenter or axis, and the other finger on the same blade may be bent simi-This curving of the fingers serves to detach'portions of packed snow,when encountered, from the mass in advance of the blades, so that theyare drawn into the rotor and thrown through the chute as described.Beyond the ends of the finger with the parts properly proportioned,

the snow or slush does not ordinarily become packed sufiiciently toprevent its further movement toward the rotor.

When the hood 60 is adjusted all the way toward the right, its outerpart is inclined downwhen desired. In the movement of the snow and airby the rotor, the snow takes a course next the curved outer side of thecasing and then follows the chute plate55 and hood portion 60, while theair current produced sweeps along against the underside of thistravelling body of snow, affording a support and carrier means therefor,causing it to travel a great distance in proportion to the size andpower of the apparatus. This formation of the travelling air support andcarrier is due to the formation of the very high opening 58, which ismuch larger than required solely for the discharge of the snowexcavated, even at the highest travelling speed of the tractor. A freeexit for the air below and in line with the snow is thereby provided,and in addition, a portion of air in currents at lower levels wherebyeddy currents impeding the progress of the major body of air at itsunder side are minimized.

The machine may be readily steered for gradual turns and slight curvesby lateral pressure on the handles 22 while the machine progresses, butfor an abrupt turn it is easier to position the machine by elevating theplow, which is accomplished by downward pressure on the handles Thedepression of the handles 22 will lift the bracket 21 against the upperspring 31, compressing the latter somewhat, and through it lifting theframe 30 and plow elements. This will enable the side shoe plates to belifted clear of the bed of snow beside the machine, so that it may beturned as required by swinging the plow in the proper direction. Whenthe plow is lowered, if a substantially planiform pavement is involved,the forward part of the plow or blade and runner ll-12 will tend toengage the pavement first while the blades 66-61 and the blade andrunner 64-16 are still elevated. As the compression of the spring 31 bythe bracket 21 is relieved, however, the pivoted end of the frame 30 at2526 moves further downward until the rear runner shoe I5 at the righthand side of the machine engages the ground. This support, and the lowerspring 36 then being compressed sufficiently, checks further relativemovement of the parts. Owing to the balance of the tractor unit on itsaxle, or the fact that it is heavier at the rear part, it serves to, inpart at least, counter balanc the weight of the plow unit power plant.The weight on the forward part of the tractor frame is not sufficient todepress the pivot I! further.

and there is no rocking of the plow unit on the shoe l6 and lifting ofthe forward part of the plow. However, if the forward runner shoe 1!encounters a rise of surface of the pathway or roadway it is lifted, andthe weight of the rear of the plow unit at the pivotal connection withthe tractor unit causes the rear part of the plow to drop, moving thetractor unit on its axle so that the bracket 21 is depressed slightlycompressing the lower spring 36. When the forward shoe I2 passes oversuch a rise, relief of support thereof, while the rear shoe l5 restsupon the surface at its higher part causes the forward part of the plow.to fall, elevating the forward part of the tractor unit and pivot 26,the bracket 21 moving slightly upward and compressing the upper spring31 while relieving the lower one 36. The handles 22 become lowered atthesame time. These movements may be facilitated, if necessary, by

. corresponding manipulations of the handles by moderate pressure orslight lifting movement thereof. While in the present instance the rotorextends from the extreme side of the swath to the middle thereof, thediameter of the rotor may be made still smaller relative to the width ofthe swath, still keeping it close to one side, and the plow 10 beingmade relativelylonger. It may be operated from the tractor power plant,if preferred.

The device has been made in various sizes, as indicated, and in oneexample, suitable for clearing sidewalks, has an overall width of threefeet from the plane of the side shoe plate .62 to the plane of the sideshoe plate 69, while the plow I0 is approximately fifteen inches inheight at its extremity and 22 inches in height at its junction with thecasing 6| of the rotor. This particular size of the device is effectivein snows ranging in depth from one or two inches to one foot or more. Inthe latter cases, the weight of fresh fallen snow above the plow 10causes it to fall toward the device as the latter advances and the snowat the side next the plow falls toward the right and is drawn into therotor before the plow penetrates materially under the snow. Where snowcenter fore-and-aft line or axis of the plow unit is a material factorin enabling the ready handling of the device to cut a straight path, forthe reason that owing to the function of. the rotor, the latter relievesimpedanceof the snow to forward progression of the device at that side,and the snow pressure of the great lateral reach of the plow 10 wouldtend to be unbalanced and to turn the machine toward the left; whereas,with the tractor located off center in the direction in which the plow10 projects laterally, this tendency is overcome and the machine tendsto move ahead in a straight path. When the diameter of the rotor is madesmaller in proportion to the total width of the swath, the location ofthe tractor unit may be more toward the right. The offset of the plowunit from the axis of the tractor unit is proportionate to thedifference between the dialrfigter of the rotor and total width of theplow u The machine may be easily steered while progressingforwardly byappropriate lateral pressure on the handles 22, although an abrupt turncan be more readily made by first elevating the Plow.

The height of the opening 58 from the edge 54 to the outer edge of thehood 88 when the latter is fully retracted has been two feet in athreefoot-swath, and the diameter of the rotor has been made eighteeninches. The disc 8| has been produced in plate steel. and the blades 83have been produced from inch thick cold rolled steel plate, but may bemade from special steels of various kinds, and if made of a rustlessalloy will have advantages in'preserving a smooth face at the concaveand adjacent fiat surfaces on which snow may slide freely.

While a specific embodiment of the invention has been disclosed, it willbe understood that this is purely exemplary, and that variousmodifications of construction, substitution, and changes of proportionsmay be made without departing from the spirit of the invention, as moreparticularly set forth in the appended claims.

The device may be arranged to be attached to other forms of tractors,including four-wheel type, with appropriate modification of coupling,

and may be used for highway clearing and other large scale excavationoperations, including wagon or truck loading.

In addition to the turning movement due to differences in resistance-toforward progression of the machine at opposite sides, there is also aresultant of the lateral pressure of material against the plow arm 18,which tends to swing the machine toward the left. This is opposed by theside shoe plate 88 at the end of the arm, and maybe further corrected byan inclination of the side shoe plate 68 laterally inward toward thefront, if necessary. I

In order to minimize liability of serious damage, the rotor disc 8| issecured to the shaft 46 by means of a pin 80 of a material adapted to besheared by the hub 82 and the shaft 48 of the rotor when an excessivestrain is imposed thereon.

The disc 8| performs an important function in preventing retardance ofthe rotor by snow which might become packed or frozen against the backwall of the casing, where such adhesion ismore likely to occur thanelsewhere (due to slower movement of snow adjacent the axis of therotor), and where it is less likely to be cleared, because the pressureof snow thereagainst is less than at the periphery of the case. In theoperation of the rotor, therefore, movement of snow rotatively orradially will not be opposed by snow on the back wall of the casing, andsnow particles which become attached to the disc 8| are caused therebyto be moved at maximum speed so that the greatest possible centrifugalforce is developed therein, by which its movement from the disc will befacilitated under normal operation of the machine.

The disc 8| is shown as formed with a multiplicity of apertures 81 whichmay be omitted if desired, constituting air inlets, and the back wall ofthe case may be suitably ported within the zone of the disc to admit airtherethrough in case this is found desirable. The effect of theapertures 81 is that air is'drawn from the rear forwardly through thedisc all by the vacuous condition produced between the blades of therotor by the outrush of snow and air therefrom,

- acted, so that the,snow is kept free for movement radially along theblades 83.

The tractor frame andwheels with the runners of the plow unit may beconsidered broadly a truck, and if desired, wheels may be substitutedfor the runners and 18, especially where the machine is to be used forother material than and a film of air is formed next the disc by whichpressure of the snow thereagainst is countersnow. It may be used as ascraper for dirt surfaces, and for clay scraping where weathered claysurface is to be moved or gathered, as in brick-making. The device mayalso be found useful in conditioning sea beaches, for taking up surfacesand and redistributing it with an untracked surface, and for removingpaper and other trash from the sand.

It will be understood that the term fixed in the claims relates only tothe position of parts at a given adjustment and does not limit relativeadjustment of parts which at other times are relatively fixed. r

We claim:

1. In a machine of the character described wherein there is a two-wheeltractor unit having rearwardly located single axis wheels and a plowunit mounted in front thereof: the structure wherein the plow unitincludes a rigid truck frame extended to an intermediate position on thetractor unit, a pivotal connection between 2. In a machine of thecharacter described, a.

plow unit, means to propel the same, a laterally located rotarycentrifugal excavator-thrower device thereon having arotor mounted on aforeand-aft axis and open toward the front with the periphery of itsrotor at one extreme side of the unit, and a lateral diagonal pusherplow device extended from the opposite side of the excavatorthrowerdevice, its inner end in delivery relation to the excavator-throwerdevice, said excavatorthrower device having a substantially circularcase partly surrounding the rotor, and open at the upper part adjacentthe outer side of the excavator-thrower device from a line inwardly ofthe axis of the rotor closely adjacent the level of the top of the rotorto a vertical plane substantially tangent to the rotor at its outerside, said case having an upstanding chute consisting of a fixed innerchute wall inclined laterally of the unit from the first named linesubstantially at a tangent to the rotor periphery, and parallel back andfront chute walls of thev same height joined to the inclined wall andjoined to said case, the space between said front and back walls at theouter side of the unit being open from said first named opening in saidcase to the extremity of the inclined wall.

3. The structure of claim 2 in which said rotor rotates to move at itsupper side in the direction of the outer side of the excavator-throwerdevice, and is constructed to admit air at its inner part from adirection other than that of incidence of the material delivered theretoto be thrown, whereby a substantially large body of air is projectedwith the thrown material passing through the chute, as a supportingstratum and carrier.

4. The structure of claim 2 in which a hood is pivoted on the upper partof said chute on an axis substantially spaced below the apex of thechute, said hood having side walls closing the sides thereof adjacentsaid front and back walls, and a curved transverse wall close to theextremity 0f said'inclined wall, said hood being movable from a positionwith the outer edge of its curved wall closely. adjacent the inclinedchute wall to positions variously extended laterally and downwardly.

5. In a machine of the character described a two wheeled truck tractorunit, a plow unit including a. rigid frame having two rigid side membersprojecting rearwardly therefrom at respective sides of the tractor unit,a pivot coupling between the tractor unit and extremities of the saidside members of the plow, the tractor unit having a part projected asubstantial distance forwardly from the pivot coupling, and springs overand under said projected part seated on the plow frame for the purposesdescribed, said projected part being removably engaged between thesprings.

LESLIE G. MORSE.

ARTHUR R. HILL,

CHARLES C. MORSE.

